Radiated Tortoise

Range:

Southern portion of the island of Madagascar.

Habitat:

Dry regions of brush, thorn bushes and woodlands.

Characteristics:

The radiated tortoise has an oval, extremely elevated, smooth carapace. Each of the shields bears a distinct pattern of alternate radiating bands of yellow and dark brown. Usually the yellow lines are narrower than the brown, but sometimes the reverse is the case. In very large specimens, the characteristic pattern might be missing; also some entirely yellowish specimens have been recorded. The radiant pattern is also visible on the sides and on the plastron (under shell). The head is yellow with a black top. The tail is ending with a spur-like scale.Males can be distinguished by their longer tails and a notch in the under shell (plastron), below the tail.

These tortoises have strong beaks and thick skin to be able to eat their favorite foods, like cactus pads.

The shell is supplied with blood vessels and nerves so like other tortoises, it can feel when being touched.

Behavior:

Radiated tortoises are diurnal, like warmth, drink a lot whenever they get the opportunity. They can however, go long periods without water. During the hottest parts of the year, they will burrow to avoid dehydration and the excessive heat.

The radiated tortoise is a grazing herbivore. They feed during the day primarily on grasses, fruit and succulent plants, which form 80 to 90 percent of their diet. A favorite food in the wild is the Opuntia cactus. They are known to graze regularly in the same area, thus keeping the vegetation in that area closely trimmed. They seem to prefer new growth rather than mature growth because of the high-protein, low-fiber content.

Reproduction:

Male are able to breed when they reach lengths of about 12 inches; females are often a few inches longer. Rival males will fight during the breeding season and attempt to roll one another onto their backs. They initiate courtship by a head-bobbing display and smelling the female's hind legs. This is followed by energetic circling and butting of the female's carapace. In some cases the male may lift the female up with the front edge of his shell to keep her from moving away.

The male then mounts the female and mating is accompanied by hissing and grunting by the male. Females lay from three to 12 ball-shaped eggs in a nest she has dug that is six to eight inches deep. She does not stay to guard the nest.
Five and eight months later the eggs hatch and the young measure 1.25 to 1.6 inches at hatching. Unlike the yellow coloration of the adults, the juveniles are a white to an off-white shade. Juveniles attain the high-domed carapace soon after hatching.

Interesting Facts:

The shell is supplied with blood vessels and nerves it can feel when being touched.

The people of Madagascar call the tortoise a sokake.

One traditional Mahafaly story states: Tortoises bring the rains—God sends rains, not for the humans, who can look after themselves, but for the animals, like the tortoises, who need the rain and God’s help. When there are no more animals, there will be no more rain.

Like a tree, the tortoise adds growth rings to its scutes (bony plates that form the shell) as it ages.

When radiated tortoises feed on prickly pears, an invasive plant that grows rampant in Madagascar, the dark red fruit leaves a stain on their mouth that looks like lipstick.

Conservation:

Unfortunately, these tortoises are severely endangered due to loss of habitat, being poached for food, and being over exploited in the pet trade. International collection has been documented with Asian smugglers collecting tortoises for the pet trade and for their livers. The burning of the tortoise’s spiny forest home for charcoal production is also threatening the species.

However, domestic utilization of this species is of greater concern. Within Madagascar, the Mahafaly and the Antandroy, whose land covers the range of the radiated tortoise do not utilize the tortoise. They have a taboo (termed a 'fady') against eating or touching the tortoises. However, large numbers of radiated tortoises are gathered by people from other areas of Madagascar who recently moved into this region, or by Malagasy people who are passing through. It is estimated that more than 45,000 adult radiated tortoises are harvested each year. Besides being used as food, the Malagasy often keep the tortoises as pets and in pens with chickens and ducks as a means of warding off poultry diseases.

They are part of a Species Survival Plan(SSP) in North American Zoos. Captive breeding has shown great promise. There are 1405 specimens listed in the North American regional studbook and this population is managed by an SSP captive breeding program. Captive breeding to create an assurance colony for the future as well as helping the Madagascar people to conserve this species are some of the goals for the SSP.